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New  aad  Little  Known  Trees 
Suitable  for  Southern 
California  Avenues 


AGRiC.  DEPT. 


1911  POMONA  COLLEGE  JOURNAL  OF  ECONOMIC  BOTANY,  VOL.  I,  No.  4,  DECEMBER. 


New  and  Little  Known  Trees  Suitable  for 
Southern  California  Avenues 

DR.    C.   F.   FRANCESCHI 
SANTA  BARBARA,   CALIFORNIA 

Southern  California  has  started  at  last  to  build  good  roads,  and  there  is  no 
reason  whatever  why  we  should  not  have  them  as  perfect  as  any  in  the  world, 
because  we  are  able  to  employ  the  best  talent  and  the  best  materials,  while  our 
exceptionally  equable  climatic  conditions  are  ideal  for  the  maintenance  of  good 
roads. 

If  we  need  perfect  roads  we  also  need  them  to  be  beautiful,  and  it  is  obvious 
that  more  careful  attention  is  going  to  be  bestowed  on  the  selection  of  trees  which 
will  prove  best  adapted  either  for  ornament  or  for  shade. 

Everybody  in  Southern  California  is  aware  of  the  fact  that  we  are  able  to 
draw  upon  almost  any  part  of  the  world  for  ornamental  trees,  just  as  we  do  for 
all  sorts  of  shrubs  and  other  plants.  Consequently,  there  will  be  much  too  many 
for  this  especial  purpose.  In  this  paper  I  am  going  to  mention  only  such  trees 
as  have  already  proven  themselves  particularly  desirable  for  planting  along 
avenues  or  roadways  of  considerable  length,  and  between  sixty  to  one  hundred 
feet  wide. 

The  selection  of  trees  best  adapted  for  planting  on  streets  in  the  residence 
sections  of  our  towns  is  obviously  subject  to  more  special  requirements  and 
restrictions,  and  will  not  be  treated  in  this  paper.  The  question  whether  in 
Southern  California  deciduous  trees  must  entirely  be  supplanted  by  evergreens 
I  am  not  going  to  discuss,  believing  that  either  one  class  or  the  other  might  be 
preferable  under  different  conditions. 

As  I  understand  it,  the  beauty  of  an  avenue  of  trees  resides  principally  in 
their  uniform  growth  and  in  each  individual  tree  being  allowed  to  display  its 
particular  character  and  features,  and  not  to  become  entangled  with  its  neighbors. 

Along  such  avenues,  sixty  to  one  hundred  feet  wide,  and  which,  very  likely, 
will  not  have  cemented  or  asphalted  sidewalks,  trees  which  will  eventually  attain 
sixty  to  one  hundred  feet  in  height  will  not  be  objectionable,  even  if  they  grow  a 
very  big  trunk. 

Native  Evergreen  Trees 

The  following  California  native  trees  have  already  been  planted  on  a  more 
or  less  extensive  scale  and  are  sure  to  prove  satisfactory: 

Prunus  integrifolia,  "Island  Cherry,"  "Islay,"  by  some  botanists  considered 
to  be  only  a  form  of  the  "mountain"  or  "wild  cherry,"  but  a  native  (exclusively) 
of  Santa  Cruz,  Santa  Rosa  and  Santa  Catalina  islands.  Of  rapid  and  pyramidal 
growth,  the  glossy  foliage  much  varying  in  shape  and  size,  but  never  holly-like. 
Will  thrive  in  almost  any  kind,  of  soil,  and  stand  well  heavy  winds.  May  attain 
sixty  to  eighty  feet;  should  be  planted  twenty-five  to  fifty  feet  apart. 

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202  POMONA  COLLEGE  JOURNAL  OF  ECONOMIC  BOTANY 

Quercus  agrifolia,  the  common  "California  Live  Oak,"  will  grow  fast  enough 
in  tolerably  good  soil,  and  with  plenty  of  moisture  at  the  roots;  in  poor  and  dry 
soil  will  develop  slower  but  will  attain  large  size  and  a  great  age,  as  shown  by 
the  huge  trees  among  the  sandstone  boulders  on  the  ridge  at  Montarioso.  May 
attain  sixty  feet,  or  over ;  being  of  spreading  habit,  should  be  planted  not  less 
than  forty  feet  apart. 

Quercus  chrysolepis,  "Golden-leaf  Oak,"  "Canyon  Live  Oak,"  generally  found 
higher  up  in  the  mountains  than  the  preceding,  and  attaining  about  same  size, 
but  not  such  a  fast  grower. 

Lyonothamnus  ftoribundus  var.  asplenifolius,  "Palo  Fierro"  or  "Ironwood" 
of  Santa  Cruz  and  Santa  Rosa  islands ;  of  regularly  pyramidal  shape,  very  con- 
spicuous for  its  aromatic,  fern-like  foliage,  and  large  umbels  of  white,  strong 
scented  flowers.  May  attain  fifty  feet  and  over,  should  be  planted  twenty  or 
twenty-five  feet  apart. 

Umbellularia  californica,  "Native  Bay"  or  "Laurel,"  of  dense,  columnar 
growth,  quite  heavily  foliaged,  the  strong  scented,  deep  green  leaves  persisting  for 
several  years.  Will  not  succeed  far  from  water,  may  attain  sixty  to  eighty  feet, 
and  occasionally  much  more,  like  the  gigantic  specimen  at  Cathedral  Oaks,  five 
miles  north  of  Santa  Barbara.  Should  be  planted  twenty-five  or  thirty  feet  apart. 

Chamaecyparis  larvsoniana,  "Lawson  Cypress."  Surely  one  of  the  most  de- 
sirable among  conifers,  on  account  of  its  feathery  branches  and  pleasant  green 
color.  Will  succeed  even  in  poor  soil  and  with  little  moisture,  but  much  better 
under  more  favorable  conditions.  To  retain  its  full  beauty,  not  unlike  most  other 
conifers,  its  lower  branches  ought  to  be  allowed  to  droop  to  the  ground,  and 
therefore  it  should  not  be  planted  at  less  than  forty  feet.  There  is  no  doubt  that 
the  most  picturesque  effect  will  be  obtained  if  conifers  are  used  only  on  sloping 
ground,  in  which  position  they  will  also  thrive  much  better. 

Libocedrus  decurrens,  "Incense  Cedar,"  another  very  tall  native  conifer, 
more  columnar  in  habit  than  the  preceding,  and  not  such  a  fast  grower.  Could  be 
planted  twenty-five  to  thirty  feet  apart.  Not  of  feathery  effect,  but  the  emerald 
green  of  its  foliage  is  very  attractive. 

Exotic  Evergreen  Trees 

A  certain  number  of  conifers  belong  to  this  section,  which  have  been  planted 
more  or  less  in  our  gardens  and  parks,  but  hardly  at  all  for  avenues. 

Araucaria  excelsa,  the  "Norfolk  Island  Pine"  or  "Star  Pine,"  leads  the  list 
for  its  wonderful  beauty  and  fast  growth.  I  do  not  know  of  any  other  tree,  no 
matter  from  whatever  country,  possessing  such  a  distinctiveness  of  character,  and 
such  a  solemnity  of  outline.  But  it  could  not  be  used  for  avenues  under  one 
hundred  feet  wide,  and  should  be  planted  from  sixty  to  eighty  feet  apart.  It  is 
not  at  all  particular  about  soil,  as  shown  in  Santa  Barbara  where  most  numerous 
and  most  beautiful  specimens  are  growing,  both  in  the  rich  moist  soil  down  town 
and  on  the  dry  hard-pan  in  the  upper  part  of  town. 

Araucaria  bidrvillii,  the  "Bunya-bunya"  of  Queensland,  will,  at  least  in  this 
country,  grow  not  as  tall  and  much  slower  than  the  preceding,  and  it  appears  to 
need  also  deeper  soil  and  more  moisture.  But  it  is  most  impressive  for  its  dense 


POMONA  COLLEGE  JOURNAL  OF  ECONOMIC  BOTANY  203 

pyramids  of  a  dark  green  color.     Should  be  planted  not  less  than  fifty  feet  apart. 

Cunninghamia  sinensis,  from  China,  offers  about  the  same  outline  as  A. 
bidwillii,  but  with  branches  more  drooping,  the  foliage  of  distinctly  glaucous  color. 
It  will  stand  more  cold  and  more  heat,  but  needs  deep  soil  and  plenty  of  moisture 
at  the  roots,  otherwise  losing  its  lower  branches  and  looking  very  unsightly.  The 
finest  specimens  that  I  know  of  are  at  the  Tevis  place  near  Bakersfield,  where 
the  range  of  temperature  is  pretty  wide,  but  soil  is  deep  and  moist.  Plant  fifty 
feet  apart. 

Cedrus  deodara,  or  "Himalayan  Cedar,"  is  well  known  in  gardens,  but  has 
never  been  much  used  as  an  avenue  tree.  I  know  only  of  the  Santa  Rosa  avenue 
in  Altadena,  which  is  certainly  very  striking,  but  the  effect  is  spoiled  by  the  avenue 
not  being  wide  enough  and  by  the  trees  having  been  set  much  too  close  together. 
It  should  not  be  less  than  forty  feet. 

Cupressus  sempervirens,  the  "Italian"  or  "Oriental  Cypress,"  has  been,  of 
late  much  used  (and  abused)  in  California  gardens.  It  is  sure  to  make  splendid 
•venues,  like  those  of  the  most  ancient  and  more  beautiful  villas  in  Italy,  but  one 
must  not  forget  that  in  rich  soil  and  with  plenty  of  moisture,  it  is  sure  to  lose  its 
character  and  "to  grow  fat,"  its  lateral  branches  spreading  out  under  the  over- 
weight of  foliage ;  also  that  the  full  effect  of  a  cypress  avenue  cannot  be  obtained 
in  only  a  few  years.  The  spreading  form  of  the  Italian  cypress,  much  despised 
in  California,  will  make  splendid  trees,  even  in  the  poorest  soil,  having  the  same 
outline  and  offering  the  same  scenic  effect  as  firs  and  spruces,  which  are  an 
impossibility  here.  If  planted  in  rich  and  moist  soil  Cupressus  horizonthalis  will 
be  at  its  best,  displaying  more  fully  its  above  mentioned  character.  The  "columnar" 
form  can  be  planted  as  close  as  sixteen  or  twenty  feet,  the  "spreading"  one  will 
require  at  least  twice  as  much. 

Cupressus  guadalupensis,  "Blue  Cypress"  of  Guadalupe  island,  not  over 
seventy  feet  in  height,  and  normally  of  a  peculiar  "ovoidal"  outline,  at  least  up  to 
a  certain  age.  Particularly  recommendable  for  dry,  rocky  locations,  growing 
naturally  upon  disintegrated  lava  currents.  Quite  "blue"  in  the  young  age,  and 
its  bark  peeling  off,  just  like  cherry  trees  and  Araucaria  cunninghamii.  With  age 
it  is  much  liable  to  vary,  both  in  color  and  in  outline,  as  I  had  the  opportunity 
of  remarking  when  in  Guadalupe  island  many  years  ago.  Plant  from  twenty-five 
to  forty  feet  apart. 

Cupressus  arizonica,  (Figure  80),  from  the  mountains  in  northern  Arizona, 
will  retain  its  silvery  color,  better  than  the  preceding.  It  will  grow  not  quite 
as  tall  and  will  spread  more  at  the  base,  while  it  will  stand  much  more  cold  and 
any  amount  of  drought.  Plant  from  thirty  to  forty  feet  apart. 

Australian  Eucalyptus  are  recommendable  for  avenues,  including  the  common 
E.  globulus,  "Blue  Gum,"  which  to  this  date  has  been  used  along  roadways, 
probably  more  extensively  than  any  other  tree  but  rather  as  a  most  effective  wind- 
break than  for  beautifying  the  same.  The  following  kinds  appear  to  be  more 
particularly  recommendable  for  avenues : 

Eucalyptus  citriodora,  "Lemon-scented  Gum,"  quite  unique  for  its  smooth, 
ivory  white,  tapering  trunk,  rising  to  one  hundred  and  fifty  feet,  and  for  its 


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POMONA  COLLEGE  JOURNAL  OF  ECONOMIC  BOTANY 


comparatively  small  but  very  regular  crown,  from  which  such  delicious  perfume 
exhales  in  foggy  weather.     Should  be  planted  thirty  to  forty  feet  apart. 

Eucalyptus  rostrata,  "Red  Gum,"  almost  as  fast  a  grower  as  the  "Blue 
Gum,"  and  having  the  advantage  of  standing  more  cold  in  the  young  stage,  and 
of  being  more  graceful  in  shape  and  more  uniform  when  full  grown.  Plant 
about  forty  feet  apart. 


Figure  80.    Cupressus  arizonica  on  its  dry  native  heath. 

Eucalyptus  cornuta,  "Yate,"  up  to  eighty  feet  high;  highly  recommendable 
not  only  for  its  standing  saline  and  alkaline  soil  better  than  any  other,  but  also  for 
the  very  peculiar  shining  and  plumy  effect  of  its  foliage.  Should  be  planted  at 
about  forty  feet  apart. 

Eucalyptus  botryoides,  "Bastard  Mahogany,  up  to  one  hundred  feet;  a 
handsome,  symmetrically  shaped  tree,  standing  drought  well.  Plant  at  forty  feet. 


POMONA  COLLEGE  JOURNAL  OF  ECONOMIC  BOTANY  205 

Eucalyptus  saligna,  "Grey  Gum,"  up  to  one  hundred  feet,  of  weeping  effect 
like  the  "weeping  willow/'  leaves  also  willow  shaped.  Plant  at  about  forty  feet. 

There  are  also  a  number  of  species  of  Ficus,  "rubber  trees,"  from  different 
countries  which  are  particularly  suitable  for  wide  avenues. 

Ficus  macrophylla,  "Moreton  Bay  Fig,"  is  the  most  widely  known,  and  it 
makes  a . magnificent  tree,  as  one  can  judge  from  the  few  large  specimens  which 
escaped  destruction  during  the  wonderful  extension  of  building  in  our  Southern 
California  cities.  This  should  not  be  spaced  under  seventy-five  to  eighty  feet, 
and  it  should  be  excluded  from  locations  subject  to  heavy  winds  which  may  break 
too  easily  its  heavily  laden  limbs. 

Ficus  rubiginosa  or  australis,  also  from  Australia,  will  grow  not  as  large.  It 
has  also  smaller  leaves,  and  it  will  stand  more  cold;  will  also  stand  the  wind  much 
better.  Plant  from  forty  to  fifty  feet  apart. 

Ficus  bellingeri,  from  Queensland,  appears  to  be  a  decided  improvement  on 
the  preceding,  but  there  are  no  large  enough  specimens  as  yet  to  form  a  positive 
j  udgment. 

Ficus  retusa,  from  India  and  Southern  China  (synonym  F.  nitida),  is  prob- 
ably the  species  which  has  gained  the  widest  reputation  as  an  avenue  tree.  Much 
planted  at  Hongkong,  in  Algeria  and  in  Sicily;  there  used  to  be  some  fine  speci- 
mens in  the  center  of  Los  Angeles,  which  had  to  give  room  to  sky  scrapers. 
It  appears  not  to  grow  as  fast  as  F.  macrophylla;  its  foliage  is  thick  and  somewhat 
in  the  shape  of  the  "strawberry  guava."  It  will  need  good  soil,  plenty  of  moisture 
and  plenty  of  heat  to  develop  in  the  proper  way.  Plant  at  about  forty  feet  apart. 

Hymenosporum  flavum,  Queensland,  up  to  one  hundred  feet;  related  to  the 
Pittosporums ,  but  finer  than  any  of  them.  Fast  and  pyramidal  growing,  its 
branches  slightly  drooping  and  laden  in  spring  with  a  profusion  of  jasmine  shaped 
and  jasmine  scented,  yellow  flowers.  Not  at  all  particular  about  quality  of  soil, 
but  not  recommended  for  very  dry  places.  Plant  at  thirty  or  forty  feet  apart. 

Pittosporum  rhombifolium,  Queensland,  up  to  eighty  feet  high;  probably  the 
tallest  and  the  handsomest  of  all  kinds  introduced  so  far,  not  only  for  its  very 
regular  pyramidal  shape,  and  peculiar  foliage,  but  also  for  the  great  profusion 
of  its  yellowish  white,  fragrant  flowers  in  summer,  and  of  its  shining  bright  yellow 
berries  which  persist  almost  all  winter.  Plant  at  thirty  or  forty  feet  apart. 

Quercus  suber,  the  "cork  oak"  of  the  Mediterranean  basin.  It  has  about  the 
general  outline  of  our  native  live  oak,  but  will  make  faster  growth,  and  is  also 
interesting  for  its  bark.  Plant  forty  feet  apart. 

Sterculia  gregori,  (Figure  81),  from  Western  Australia;  the  very  best  of  all 
kinds  of  Sterculia  or  Brachychiton,  "bottle  trees,"  "flame  trees,"  introduced  so 
far,  the  finest  specimen  to  be  seen  at  Alhambra.  Clothed  down  to  the  ground  with 
glossy,  coriaceous  foliage  which  persists  for  many  years,  and  sets  out  well  the 
heavy  bunches  of  salmon  colored  flowers  which  are  produced  for  several  months. 
May  attain  one  hundred  feet  in  height.  Plant  at  forty  or  fifty  feet. 

Pircunia  dioica,  Argentina,  the  "Ombu"  of  the  Pampas,  "Bella  Sombra"  of 
the  Spaniards  who  introduced  it  to  Europe.  In  good  soil  will  beat  almost  all  other 
trees  for  quick  growth  and  for  beautiful  shade,  but  will  also  stand  drought  won- 


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derfully  well.     It  will  in  time  build  huge  buttresses  at  the  base,  like  those  of  many 
species  of  tropical  Ficus.     Should  be  planted  about  fifty  feet  apart. 

Tipuana  speciosa,  Argentina,  there  called  "Tipa,"  and  considered  one  of  the 
finest  among  native  trees.      May  attain  one  hundred  feet,  and  builds  a  straight 


Figure  81.     Sterculia  gregori  at  Alhambra,   California. 

trunk,  crowned  by  feathery  foliage  of  light  green  color  and  drooping  bunches  of 
yellow  flowers.     Plant  about  forty  feet  apart. 


POMONA  COLLEGE  JOURNAL  OF  ECONOMIC  BOTANY 


207 


Dendrocalamus  latiftorus,  from  the  island  of  Formosa,  "upright  giant 
bamboo."  For  low  lands,  and  even  where  moisture  might  be  excessive  for  other 
trees,  clumps  of  this  giant  bamboo  will  make  magnificent  avenues,  in  the  same  way 
as  they  will  make  the  most  efficient  wind  breaks  (if  planted  closer  together).  Does 
well  also  on  drier  ground,  as  can  be  seen  in  Montecito,  etc.  For  avenues  should 
be  planted  thirty  to  fifty  feet  apart. 

Deciduous  Trees 

Acer  macrophyllum,  California.  This  has  broader  leaves  than  any  other  kind 
of  maples  that  are  found  scattered  on  the  northern  hemisphere,  and  it  is  certainly 
one  of  the  finest.  In  order  to  grow  well  and  to  retain  its  foliage  until  late  it  will 
need  plenty  of  moisture  at  the  roots,  as  otherwise  the  leaves  will  begin  to  drop  in 
August  or  earlier.  Same  remark  applies  to  other  deciduous  trees.  This  grows  up 


Figure  82.     Cedrela  fissilis  planted  in  1897. 

to  eighty  feet,  and  should  be  planted  thirty  to  forty  feet  apart. 

Quercus  lobata,  California,  "Valley  Oak,"  "Roble"  of  the  native  Californians. 
In  deep  soil  and  with  plenty  of  moisture  this  makes  a  truly  magnificent,  widely 
spreading  tree,  but  could  not  be  used  under  different  conditions.  May  attain  sixty 
or  eighty  feet ;  should  be  planted  eighty  to  one  hundred  feet  apart. 

Platanus  racemosa,  native  "Plane"  or  "Sycamore."  While  the  oldest  trees  are 
often  distorted  in  the  most  extraordinary  ways,  young  trees  can  be  easily  trained 
to  any  desired  shape,  and  this  kind  has  a  beauty  of  its  own  unrivalled  by  other 
deciduous  trees.  It  may  attain  sixty  feet  or  more,  and  should  be  set  at  least  thirty 
feet  apart. 


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Fraxinus  velutina,  "Arizona  Ash."  Grows  fast  and  very  symmetrical  in 
shape,  with  branches  gracefully  drooping,  and  it  has  the  great  merit  of  growing 
well  in  alkaline  soil  where  hardly  any  other  tree  will  do.  Grows  up  to  sixty  feet 
or  more.  Should  be  planted  thirty  to  forty  feet  apart. 

Cedrela  fissilis,  (Figure  82),  Paraguay  and  Brazil,  "Brazilian  cedar  wood." 
For  avenues  where  not  much  shade  is  required  this  is  sure  to  be  a  first  class 
deciduous  tree,  its  trunk  rising  up  straight  to  a  considerable  height  without  branch- 
ing, the  branches  never  very  heavy  and  forming  a  symmetrical  head.  Finest 
specimen  to  be  seen  in  my  old  garden  on  State  street  in  Santa  Barbara  which  I 
planted  in  1897,  and  must  be  now  about  sixty  feet  high.  Timber  is  also  very 
valuable,  much  like  "Cuban"  or  "Spanish  Cedar,"  Cedrela  odorata.  Should  be 
planted  thirty  to  forty  feet  apart. 


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